The best use of Search@UW is when you need a large number or a variety of resources. It is also helpful when your research question spans a number of different subjects, making it difficult to choose a single-subject database.
However, not all database content is available through Search@UW. There will also be many instances in which a single-subject database will have enough content that a user will not need the multiple resources connected to Search@UW. In these cases, a single database search may be easier and more efficient.